This invention relates generally to a door retainer and alarm device and more particularly, but not by way of limitation, to a magnetic door retainer for holding a one-way or two-way swinging door in a closed position in a door frame. The device actuating an alarm when the door is opened without authorization. Heretofore, there have been various types of magnetic catches and door latches as disclosed in U.S. Pat. Nos. 2,719,050 and 2,853,331 to Teetor and 2,586,900 to Alderman. Also there are prior art magnetic door stops and magnetic touch latches described in U.S. Pat. Nos. 2,497,697 to Smith, 3,258,285 to Smith and 3,492,031 to Hutchison.
More recently a patent application Ser. No. 906,086 filed by Ronald L. Biggs and licensed by the applicant disclosed a door stay retainer having means for adjusting the depth of a groove for receiving a metal retainer bar attracted by a magnet mounted in a magnet housing in the door frame. By adjusting the depth of the groove, the force is regulated which is required for opening the swinging door in the door frame.
None of the prior art patents or the above-mentioned patent application disclose the unique structure and advantages of the improved door retainer and alarm device as described herein.